Hydraulic fluid device

Patent metadata

Field	Value
Publication number	US-10718360-B2
Application number	US-201716324432-A
Country	US
Kind code	B2
Filing date	Jun 27, 2017
Priority date	Aug 10, 2016
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

A hydraulic fluid cylinder is equipped with a cylinder tube, a piston unit, and a piston rod. The piston unit has a piston body provided with a gasket-mounting groove. A gasket member is mounted in the gasket mounting groove. The gasket member has a gasket body provided with a magnet-mounting groove exhibiting groove depth in the axial direction of the piston unit, and also has a magnet mounted in the magnet-mounting groove.

First claim

The invention claimed is:

1. A fluid pressure device comprising:
a body having a slide hole inside the body;
a piston unit movable in an axial direction inside the slide hole; and
a piston rod protruding from the piston unit in the axial direction;
wherein the piston unit includes a packing member and a piston body including a packing mounting groove in which the packing member is mounted; and
wherein the packing member includes:
a packing body comprising an elastic member and circumferentially extending over an entire circumference of the piston body in a circumferential direction of the piston body, the packing body being provided with a magnet mounting groove having a depth in the axial direction of the piston unit; and
a magnet mounted in the magnet mounting groove.

2. The fluid pressure device according to claim 1 , wherein the magnet mounting groove is formed in an area of the packing body that is not subjected to elastic compressive deformation when the packing body receives compressive load at a position between the piston body and an inner surface of the slide hole.

3. The fluid pressure device according to claim 1 , further comprising:
a rotation restricting mechanism configured to restrict rotation of the piston unit relative to the body;
wherein the magnet is disposed in the packing body over a range less than an entire circumference of the packing body in a circumferential direction of the packing body.

4. The fluid pressure device according to claim 3 , wherein the rotation restricting mechanism is a rotation prevention rod extending in the axial direction of the piston unit inside the body and inserted into the piston body.

5. The fluid pressure device according to claim 3 , wherein one of the piston body and the packing member is provided with an anti-rotation protrusion protruding in the axial direction, another of the piston body and the packing member is provided with an anti-rotation recess recessed in the axial direction, and the anti-rotation protrusion is inserted into the anti-rotation recess.

6. The fluid pressure device according to claim 3 , wherein the piston rod is rotatable relative to the piston body.

7. The fluid pressure device according to claim 1 , wherein the magnet mounting groove and the magnet each have a ring shape circumferentially extending over an entire circumference of the packing body in a circumferential direction of the packing body.

8. The fluid pressure device according to claim 1 , wherein:
the piston body includes a plurality of members including a first piston member and a second piston member; and
a combination of at least two members of the plurality of members defines the packing mounting groove.

9. The fluid pressure device according to claim 8 , wherein one or both of the first piston member and the second piston member are provided with a lightening portion having a depth in the axial direction.

10. The fluid pressure device according to claim 9 , wherein the lightening portion has a through-hole passing through only one of the first piston member and the second piston member in the axial direction.

11. The fluid pressure device according to claim 9 , wherein the lightening portion comprises a plurality of lightening portions disposed at intervals in a circumferential direction.

12. The fluid pressure device according to claim 8 , wherein the first piston member and the second piston member are castings.

13. The fluid pressure device according to claim 1 , wherein the fluid pressure device is configured as a fluid pressure cylinder, a valve device, a length-measurement cylinder, a sliding table, or a chuck device.

Assignees

• Smc Corp

Inventors

• ODAKA Tsukasa

Classifications

• F16J1/008

  with sealing lips · CPC title

• F15B15/2861

  using magnetic means · CPC title

• F15B15/2807

  Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches · CPC title

• F15B15/1452 Primary

  Piston sealings · CPC title

• F15B15/1447

  Pistons; Piston to piston rod assemblies · CPC title